Oxygen-Sensing Nox4 Generates Genotoxic ROS to Induce Premature Senescence of Nucleus Pulposus Cells through MAPK and NF-κB Pathways

Figure 3

High oxygen tension regulated the cell cycle and senescence-associated secretory phenotype of NP cells via MAPK and NF-κB signaling pathways. (a, b) Representative immunoblot analysis of p38, JNK, p65, and ERK in NP cells. High oxygen tension activated p38, JNK, p65, and ERK in NP cells. The MAPK and NF-κB signaling pathways were the downstream signaling of ROS in NP cells. (c) Representative immunoblot analysis of p53, p16, p21, and retinoblastoma protein (Rb) in NP cells. (d) The percentage of SA-β-gal-positive NP cells (). (e) Immunofluorescence staining of BrdU and percentage of BrdU-positive cells in NP cells (). (f, g) RT-qPCR analysis of matrix degradation enzymes and proinflammatory cytokines in NP cells (). NP cells were pretreated with GSH, NAC, the p38 inhibitor (SB202190, SB), the JNK inhibitor (SP600125, SP), the ERK inhibitor (U0126, U), or the NF-κB inhibitor (PDTC) for 30 min followed by high oxygen tension treatment for ROS scavenging or signaling inhibition. , value < 0.05, error bars represent standard error.

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